Good choice for Smaug's voice.
Reading the book I was never under the impression Smaug was using telepathy, I just always assumed he was talking to Bilbo through voice, the main reason being Bilbo has the ring on when he enters the lair & Smaug smells him not senses that he's there. Regarding the Weta Workshop, I can't quite believe that a talking dragon would be too hard for them to create.
Also, the glimpse of Smaug at the end of the 1st movie, it doesn't look like he has the red eyes. One of my everlasting impressions of Smaug is his red eyes being quite menacing & unsettling.
But, you know, I don't like to be picky about these things. I'll it watch & enjoy all the same.